1. Field of the Inventions
This application relates generally to covers for vehicle beds and more specifically to pick up truck bed covers.
2. Description of the Related Art
Covers for vehicles having open beds such as pick up trucks are referred to as “tonneau” covers. In some configurations of tonneau covers, a single sheet cover is pivotally hinged to a front wall of the pick up truck bed. To assist with opening the cover and maintaining an open position, struts can couple the tonneau cover to side walls of the pick up truck bed. These tonneau covers shelter cargo stored in the vehicle bed from the elements, but are often prone to cracking, crazing, or other damage when used on a vehicle. Typically the tonneau covers are supported only about their peripheries by the front wall, side walls, and tailgate of the vehicle bed, and unsupported in their central area. Thus, once set in motion by road vibrations and bumps encountered by a moving vehicle, the large unsupported span of tonneau cover can exhibit the oscillatory behavior of a drum head. These repeated oscillatory cycles can lead to damage to the tonneau cover.
Various attempts have been made to strengthen or stiffen pick up bed tonneau covers. For example, attempts have been made to integrate a sheet-based tonneau cover with a truss-like structure consisting of a plurality of intersecting beams. While these additions to the tonneau covers can provide a stiffened structure, they can produce other problems such as concentrations of structural weaknesses at certain points and/or increased weight. Increased weight can necessitate increased effort to open the tonneau cover and, in turn, can require higher compression gas shock absorbers or higher strength struts. Additionally, increased weight can make installation and removal of the tonneau cover exceedingly time consuming and cumbersome. Moreover, even with the incorporation of truss-like structures to a tonneau cover, the tonneau covers are often still prone to cracking at points of stress concentration overlying the reinforcing beams.